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  <div class="section" id="module-email.message">
<span id="email-message-representing-an-email-message"></span><h1>19.1.1. <a class="reference internal" href="#module-email.message" title="email.message: The base class representing email messages."><tt class="xref py py-mod docutils literal"><span class="pre">email.message</span></tt></a>: Representing an email message<a class="headerlink" href="#module-email.message" title="Permalink to this headline">¶</a></h1>
<p>The central class in the <a class="reference internal" href="email.html#module-email" title="email: Package supporting the parsing, manipulating, and generating email messages, including MIME documents."><tt class="xref py py-mod docutils literal"><span class="pre">email</span></tt></a> package is the <a class="reference internal" href="#email.message.Message" title="email.message.Message"><tt class="xref py py-class docutils literal"><span class="pre">Message</span></tt></a> class,
imported from the <a class="reference internal" href="#module-email.message" title="email.message: The base class representing email messages."><tt class="xref py py-mod docutils literal"><span class="pre">email.message</span></tt></a> module.  It is the base class for the
<a class="reference internal" href="email.html#module-email" title="email: Package supporting the parsing, manipulating, and generating email messages, including MIME documents."><tt class="xref py py-mod docutils literal"><span class="pre">email</span></tt></a> object model.  <a class="reference internal" href="#email.message.Message" title="email.message.Message"><tt class="xref py py-class docutils literal"><span class="pre">Message</span></tt></a> provides the core functionality for
setting and querying header fields, and for accessing message bodies.</p>
<p>Conceptually, a <a class="reference internal" href="#email.message.Message" title="email.message.Message"><tt class="xref py py-class docutils literal"><span class="pre">Message</span></tt></a> object consists of <em>headers</em> and <em>payloads</em>.
Headers are <span class="target" id="index-0"></span><a class="rfc reference external" href="http://tools.ietf.org/html/rfc2822.html"><strong>RFC 2822</strong></a> style field names and values where the field name and
value are separated by a colon.  The colon is not part of either the field name
or the field value.</p>
<p>Headers are stored and returned in case-preserving form but are matched
case-insensitively.  There may also be a single envelope header, also known as
the <em>Unix-From</em> header or the <tt class="docutils literal"><span class="pre">From_</span></tt> header.  The payload is either a string
in the case of simple message objects or a list of <a class="reference internal" href="#email.message.Message" title="email.message.Message"><tt class="xref py py-class docutils literal"><span class="pre">Message</span></tt></a> objects for
MIME container documents (e.g. <em class="mimetype">multipart/*</em> and
<em class="mimetype">message/rfc822</em>).</p>
<p><a class="reference internal" href="#email.message.Message" title="email.message.Message"><tt class="xref py py-class docutils literal"><span class="pre">Message</span></tt></a> objects provide a mapping style interface for accessing the
message headers, and an explicit interface for accessing both the headers and
the payload.  It provides convenience methods for generating a flat text
representation of the message object tree, for accessing commonly used header
parameters, and for recursively walking over the object tree.</p>
<p>Here are the methods of the <a class="reference internal" href="#email.message.Message" title="email.message.Message"><tt class="xref py py-class docutils literal"><span class="pre">Message</span></tt></a> class:</p>
<dl class="class">
<dt id="email.message.Message">
<em class="property">class </em><tt class="descclassname">email.message.</tt><tt class="descname">Message</tt><big>(</big><em>policy=compat32</em><big>)</big><a class="headerlink" href="#email.message.Message" title="Permalink to this definition">¶</a></dt>
<dd><p>If <em>policy</em> is specified (it must be an instance of a <a class="reference internal" href="email.policy.html#module-email.policy" title="email.policy: Controlling the parsing and generating of messages"><tt class="xref py py-mod docutils literal"><span class="pre">policy</span></tt></a>
class) use the rules it specifies to update and serialize the representation
of the message.  If <em>policy</em> is not set, use the <a class="reference internal" href="email.policy.html#email.policy.Compat32" title="email.policy.Compat32"><tt class="xref py py-class docutils literal"><span class="pre">compat32</span></tt></a> policy, which maintains backward compatibility with
the Python 3.2 version of the email package.  For more information see the
<a class="reference internal" href="email.policy.html#module-email.policy" title="email.policy: Controlling the parsing and generating of messages"><tt class="xref py py-mod docutils literal"><span class="pre">policy</span></tt></a> documentation.</p>
<div class="versionchanged">
<p><span class="versionmodified">Changed in version 3.3: </span>The <em>policy</em> keyword argument was added.</p>
</div>
<dl class="method">
<dt id="email.message.Message.as_string">
<tt class="descname">as_string</tt><big>(</big><em>unixfrom=False</em>, <em>maxheaderlen=0</em>, <em>policy=None</em><big>)</big><a class="headerlink" href="#email.message.Message.as_string" title="Permalink to this definition">¶</a></dt>
<dd><p>Return the entire message flattened as a string.  When optional <em>unixfrom</em>
is true, the envelope header is included in the returned string.
<em>unixfrom</em> defaults to <tt class="docutils literal"><span class="pre">False</span></tt>.  For backward compabitility reasons,
<em>maxheaderlen</em> defaults to <tt class="docutils literal"><span class="pre">0</span></tt>, so if you want a different value you
must override it explicitly (the value specified for <em>max_line_length</em> in
the policy will be ignored by this method).  The <em>policy</em> argument may be
used to override the default policy obtained from the message instance.
This can be used to control some of the formatting produced by the
method, since the specified <em>policy</em> will be passed to the <tt class="docutils literal"><span class="pre">Generator</span></tt>.</p>
<p>Flattening the message may trigger changes to the <a class="reference internal" href="#email.message.Message" title="email.message.Message"><tt class="xref py py-class docutils literal"><span class="pre">Message</span></tt></a> if
defaults need to be filled in to complete the transformation to a string
(for example, MIME boundaries may be generated or modified).</p>
<p>Note that this method is provided as a convenience and may not always
format the message the way you want.  For example, by default it does
not do the mangling of lines that begin with <tt class="docutils literal"><span class="pre">From</span></tt> that is
required by the unix mbox format.  For more flexibility, instantiate a
<a class="reference internal" href="email.generator.html#email.generator.Generator" title="email.generator.Generator"><tt class="xref py py-class docutils literal"><span class="pre">Generator</span></tt></a> instance and use its
<a class="reference internal" href="email.generator.html#email.generator.Generator.flatten" title="email.generator.Generator.flatten"><tt class="xref py py-meth docutils literal"><span class="pre">flatten()</span></tt></a> method directly.  For example:</p>
<div class="highlight-python3"><div class="highlight"><pre><span class="kn">from</span> <span class="nn">io</span> <span class="k">import</span> <span class="n">StringIO</span>
<span class="kn">from</span> <span class="nn">email.generator</span> <span class="k">import</span> <span class="n">Generator</span>
<span class="n">fp</span> <span class="o">=</span> <span class="n">StringIO</span><span class="p">()</span>
<span class="n">g</span> <span class="o">=</span> <span class="n">Generator</span><span class="p">(</span><span class="n">fp</span><span class="p">,</span> <span class="n">mangle_from_</span><span class="o">=</span><span class="k">True</span><span class="p">,</span> <span class="n">maxheaderlen</span><span class="o">=</span><span class="mi">60</span><span class="p">)</span>
<span class="n">g</span><span class="o">.</span><span class="n">flatten</span><span class="p">(</span><span class="n">msg</span><span class="p">)</span>
<span class="n">text</span> <span class="o">=</span> <span class="n">fp</span><span class="o">.</span><span class="n">getvalue</span><span class="p">()</span>
</pre></div>
</div>
<p>If the message object contains binary data that is not encoded according
to RFC standards, the non-compliant data will be replaced by unicode
&#8220;unknown character&#8221; code points.  (See also <a class="reference internal" href="#email.message.Message.as_bytes" title="email.message.Message.as_bytes"><tt class="xref py py-meth docutils literal"><span class="pre">as_bytes()</span></tt></a> and
<a class="reference internal" href="email.generator.html#email.generator.BytesGenerator" title="email.generator.BytesGenerator"><tt class="xref py py-class docutils literal"><span class="pre">BytesGenerator</span></tt></a>.)</p>
<div class="versionchanged">
<p><span class="versionmodified">Changed in version 3.4: </span>the <em>policy</em> keyword argument was added.</p>
</div>
</dd></dl>

<dl class="method">
<dt id="email.message.Message.__str__">
<tt class="descname">__str__</tt><big>(</big><big>)</big><a class="headerlink" href="#email.message.Message.__str__" title="Permalink to this definition">¶</a></dt>
<dd><p>Equivalent to <a class="reference internal" href="#email.message.Message.as_string" title="email.message.Message.as_string"><tt class="xref py py-meth docutils literal"><span class="pre">as_string()</span></tt></a>.  Allows <tt class="docutils literal"><span class="pre">str(msg)</span></tt> to produce a
string containing the formatted message.</p>
</dd></dl>

<dl class="method">
<dt id="email.message.Message.as_bytes">
<tt class="descname">as_bytes</tt><big>(</big><em>unixfrom=False</em>, <em>policy=None</em><big>)</big><a class="headerlink" href="#email.message.Message.as_bytes" title="Permalink to this definition">¶</a></dt>
<dd><p>Return the entire message flattened as a bytes object.  When optional
<em>unixfrom</em> is true, the envelope header is included in the returned
string.  <em>unixfrom</em> defaults to <tt class="docutils literal"><span class="pre">False</span></tt>.  The <em>policy</em> argument may be
used to override the default policy obtained from the message instance.
This can be used to control some of the formatting produced by the
method, since the specified <em>policy</em> will be passed to the
<tt class="docutils literal"><span class="pre">BytesGenerator</span></tt>.</p>
<p>Flattening the message may trigger changes to the <a class="reference internal" href="#email.message.Message" title="email.message.Message"><tt class="xref py py-class docutils literal"><span class="pre">Message</span></tt></a> if
defaults need to be filled in to complete the transformation to a string
(for example, MIME boundaries may be generated or modified).</p>
<p>Note that this method is provided as a convenience and may not always
format the message the way you want.  For example, by default it does
not do the mangling of lines that begin with <tt class="docutils literal"><span class="pre">From</span></tt> that is
required by the unix mbox format.  For more flexibility, instantiate a
<a class="reference internal" href="email.generator.html#email.generator.BytesGenerator" title="email.generator.BytesGenerator"><tt class="xref py py-class docutils literal"><span class="pre">BytesGenerator</span></tt></a> instance and use its
<a class="reference internal" href="email.generator.html#email.generator.BytesGenerator.flatten" title="email.generator.BytesGenerator.flatten"><tt class="xref py py-meth docutils literal"><span class="pre">flatten()</span></tt></a> method directly.
For example:</p>
<div class="highlight-python3"><div class="highlight"><pre><span class="kn">from</span> <span class="nn">io</span> <span class="k">import</span> <span class="n">BytesIO</span>
<span class="kn">from</span> <span class="nn">email.generator</span> <span class="k">import</span> <span class="n">BytesGenerator</span>
<span class="n">fp</span> <span class="o">=</span> <span class="n">BytesIO</span><span class="p">()</span>
<span class="n">g</span> <span class="o">=</span> <span class="n">BytesGenerator</span><span class="p">(</span><span class="n">fp</span><span class="p">,</span> <span class="n">mangle_from_</span><span class="o">=</span><span class="k">True</span><span class="p">,</span> <span class="n">maxheaderlen</span><span class="o">=</span><span class="mi">60</span><span class="p">)</span>
<span class="n">g</span><span class="o">.</span><span class="n">flatten</span><span class="p">(</span><span class="n">msg</span><span class="p">)</span>
<span class="n">text</span> <span class="o">=</span> <span class="n">fp</span><span class="o">.</span><span class="n">getvalue</span><span class="p">()</span>
</pre></div>
</div>
<div class="versionadded">
<p><span class="versionmodified">New in version 3.4.</span></p>
</div>
</dd></dl>

<dl class="method">
<dt id="email.message.Message.__bytes__">
<tt class="descname">__bytes__</tt><big>(</big><big>)</big><a class="headerlink" href="#email.message.Message.__bytes__" title="Permalink to this definition">¶</a></dt>
<dd><p>Equivalent to <a class="reference internal" href="#email.message.Message.as_bytes" title="email.message.Message.as_bytes"><tt class="xref py py-meth docutils literal"><span class="pre">as_bytes()</span></tt></a>.  Allows <tt class="docutils literal"><span class="pre">bytes(msg)</span></tt> to produce a
bytes object containing the formatted message.</p>
<div class="versionadded">
<p><span class="versionmodified">New in version 3.4.</span></p>
</div>
</dd></dl>

<dl class="method">
<dt id="email.message.Message.is_multipart">
<tt class="descname">is_multipart</tt><big>(</big><big>)</big><a class="headerlink" href="#email.message.Message.is_multipart" title="Permalink to this definition">¶</a></dt>
<dd><p>Return <tt class="docutils literal"><span class="pre">True</span></tt> if the message&#8217;s payload is a list of sub-<a class="reference internal" href="#email.message.Message" title="email.message.Message"><tt class="xref py py-class docutils literal"><span class="pre">Message</span></tt></a> objects, otherwise return <tt class="docutils literal"><span class="pre">False</span></tt>.  When
<a class="reference internal" href="#email.message.Message.is_multipart" title="email.message.Message.is_multipart"><tt class="xref py py-meth docutils literal"><span class="pre">is_multipart()</span></tt></a> returns <tt class="docutils literal"><span class="pre">False</span></tt>, the payload should be a string
object.  (Note that <a class="reference internal" href="#email.message.Message.is_multipart" title="email.message.Message.is_multipart"><tt class="xref py py-meth docutils literal"><span class="pre">is_multipart()</span></tt></a> returning <tt class="docutils literal"><span class="pre">True</span></tt> does not
necessarily mean that &#8220;msg.get_content_maintype() == &#8216;multipart&#8217;&#8221; will
return the <tt class="docutils literal"><span class="pre">True</span></tt>.   For example, <tt class="docutils literal"><span class="pre">is_multipart</span></tt> will return <tt class="docutils literal"><span class="pre">True</span></tt>
when the <a class="reference internal" href="#email.message.Message" title="email.message.Message"><tt class="xref py py-class docutils literal"><span class="pre">Message</span></tt></a> is of type <tt class="docutils literal"><span class="pre">message/rfc822</span></tt>.)</p>
</dd></dl>

<dl class="method">
<dt id="email.message.Message.set_unixfrom">
<tt class="descname">set_unixfrom</tt><big>(</big><em>unixfrom</em><big>)</big><a class="headerlink" href="#email.message.Message.set_unixfrom" title="Permalink to this definition">¶</a></dt>
<dd><p>Set the message&#8217;s envelope header to <em>unixfrom</em>, which should be a string.</p>
</dd></dl>

<dl class="method">
<dt id="email.message.Message.get_unixfrom">
<tt class="descname">get_unixfrom</tt><big>(</big><big>)</big><a class="headerlink" href="#email.message.Message.get_unixfrom" title="Permalink to this definition">¶</a></dt>
<dd><p>Return the message&#8217;s envelope header.  Defaults to <tt class="docutils literal"><span class="pre">None</span></tt> if the
envelope header was never set.</p>
</dd></dl>

<dl class="method">
<dt id="email.message.Message.attach">
<tt class="descname">attach</tt><big>(</big><em>payload</em><big>)</big><a class="headerlink" href="#email.message.Message.attach" title="Permalink to this definition">¶</a></dt>
<dd><p>Add the given <em>payload</em> to the current payload, which must be <tt class="docutils literal"><span class="pre">None</span></tt> or
a list of <a class="reference internal" href="#email.message.Message" title="email.message.Message"><tt class="xref py py-class docutils literal"><span class="pre">Message</span></tt></a> objects before the call. After the call, the
payload will always be a list of <a class="reference internal" href="#email.message.Message" title="email.message.Message"><tt class="xref py py-class docutils literal"><span class="pre">Message</span></tt></a> objects.  If you want to
set the payload to a scalar object (e.g. a string), use
<a class="reference internal" href="#email.message.Message.set_payload" title="email.message.Message.set_payload"><tt class="xref py py-meth docutils literal"><span class="pre">set_payload()</span></tt></a> instead.</p>
</dd></dl>

<dl class="method">
<dt id="email.message.Message.get_payload">
<tt class="descname">get_payload</tt><big>(</big><em>i=None</em>, <em>decode=False</em><big>)</big><a class="headerlink" href="#email.message.Message.get_payload" title="Permalink to this definition">¶</a></dt>
<dd><p>Return the current payload, which will be a list of
<a class="reference internal" href="#email.message.Message" title="email.message.Message"><tt class="xref py py-class docutils literal"><span class="pre">Message</span></tt></a> objects when <a class="reference internal" href="#email.message.Message.is_multipart" title="email.message.Message.is_multipart"><tt class="xref py py-meth docutils literal"><span class="pre">is_multipart()</span></tt></a> is <tt class="docutils literal"><span class="pre">True</span></tt>, or a
string when <a class="reference internal" href="#email.message.Message.is_multipart" title="email.message.Message.is_multipart"><tt class="xref py py-meth docutils literal"><span class="pre">is_multipart()</span></tt></a> is <tt class="docutils literal"><span class="pre">False</span></tt>.  If the payload is a list
and you mutate the list object, you modify the message&#8217;s payload in place.</p>
<p>With optional argument <em>i</em>, <a class="reference internal" href="#email.message.Message.get_payload" title="email.message.Message.get_payload"><tt class="xref py py-meth docutils literal"><span class="pre">get_payload()</span></tt></a> will return the <em>i</em>-th
element of the payload, counting from zero, if <a class="reference internal" href="#email.message.Message.is_multipart" title="email.message.Message.is_multipart"><tt class="xref py py-meth docutils literal"><span class="pre">is_multipart()</span></tt></a> is
<tt class="docutils literal"><span class="pre">True</span></tt>.  An <a class="reference internal" href="exceptions.html#IndexError" title="IndexError"><tt class="xref py py-exc docutils literal"><span class="pre">IndexError</span></tt></a> will be raised if <em>i</em> is less than 0 or
greater than or equal to the number of items in the payload.  If the
payload is a string (i.e.  <a class="reference internal" href="#email.message.Message.is_multipart" title="email.message.Message.is_multipart"><tt class="xref py py-meth docutils literal"><span class="pre">is_multipart()</span></tt></a> is <tt class="docutils literal"><span class="pre">False</span></tt>) and <em>i</em> is
given, a <a class="reference internal" href="exceptions.html#TypeError" title="TypeError"><tt class="xref py py-exc docutils literal"><span class="pre">TypeError</span></tt></a> is raised.</p>
<p>Optional <em>decode</em> is a flag indicating whether the payload should be
decoded or not, according to the <em class="mailheader">Content-Transfer-Encoding</em>
header. When <tt class="docutils literal"><span class="pre">True</span></tt> and the message is not a multipart, the payload will
be decoded if this header&#8217;s value is <tt class="docutils literal"><span class="pre">quoted-printable</span></tt> or <tt class="docutils literal"><span class="pre">base64</span></tt>.
If some other encoding is used, or <em class="mailheader">Content-Transfer-Encoding</em>
header is missing, the payload is
returned as-is (undecoded).  In all cases the returned value is binary
data.  If the message is a multipart and the <em>decode</em> flag is <tt class="docutils literal"><span class="pre">True</span></tt>,
then <tt class="docutils literal"><span class="pre">None</span></tt> is returned.  If the payload is base64 and it was not
perfectly formed (missing padding, characters outside the base64
alphabet), then an appropriate defect will be added to the message&#8217;s
defect property (<tt class="xref py py-class docutils literal"><span class="pre">InvalidBase64PaddingDefect</span></tt> or
<tt class="xref py py-class docutils literal"><span class="pre">InvalidBase64CharactersDefect</span></tt>, respectively).</p>
<p>When <em>decode</em> is <tt class="docutils literal"><span class="pre">False</span></tt> (the default) the body is returned as a string
without decoding the <em class="mailheader">Content-Transfer-Encoding</em>.  However,
for a <em class="mailheader">Content-Transfer-Encoding</em> of 8bit, an attempt is made
to decode the original bytes using the <tt class="docutils literal"><span class="pre">charset</span></tt> specified by the
<em class="mailheader">Content-Type</em> header, using the <tt class="docutils literal"><span class="pre">replace</span></tt> error handler.
If no <tt class="docutils literal"><span class="pre">charset</span></tt> is specified, or if the <tt class="docutils literal"><span class="pre">charset</span></tt> given is not
recognized by the email package, the body is decoded using the default
ASCII charset.</p>
</dd></dl>

<dl class="method">
<dt id="email.message.Message.set_payload">
<tt class="descname">set_payload</tt><big>(</big><em>payload</em>, <em>charset=None</em><big>)</big><a class="headerlink" href="#email.message.Message.set_payload" title="Permalink to this definition">¶</a></dt>
<dd><p>Set the entire message object&#8217;s payload to <em>payload</em>.  It is the client&#8217;s
responsibility to ensure the payload invariants.  Optional <em>charset</em> sets
the message&#8217;s default character set; see <a class="reference internal" href="#email.message.Message.set_charset" title="email.message.Message.set_charset"><tt class="xref py py-meth docutils literal"><span class="pre">set_charset()</span></tt></a> for details.</p>
</dd></dl>

<dl class="method">
<dt id="email.message.Message.set_charset">
<tt class="descname">set_charset</tt><big>(</big><em>charset</em><big>)</big><a class="headerlink" href="#email.message.Message.set_charset" title="Permalink to this definition">¶</a></dt>
<dd><p>Set the character set of the payload to <em>charset</em>, which can either be a
<a class="reference internal" href="email.charset.html#email.charset.Charset" title="email.charset.Charset"><tt class="xref py py-class docutils literal"><span class="pre">Charset</span></tt></a> instance (see <a class="reference internal" href="email.charset.html#module-email.charset" title="email.charset: Character Sets"><tt class="xref py py-mod docutils literal"><span class="pre">email.charset</span></tt></a>), a
string naming a character set, or <tt class="docutils literal"><span class="pre">None</span></tt>.  If it is a string, it will
be converted to a <a class="reference internal" href="email.charset.html#email.charset.Charset" title="email.charset.Charset"><tt class="xref py py-class docutils literal"><span class="pre">Charset</span></tt></a> instance.  If <em>charset</em>
is <tt class="docutils literal"><span class="pre">None</span></tt>, the <tt class="docutils literal"><span class="pre">charset</span></tt> parameter will be removed from the
<em class="mailheader">Content-Type</em> header (the message will not be otherwise
modified).  Anything else will generate a <a class="reference internal" href="exceptions.html#TypeError" title="TypeError"><tt class="xref py py-exc docutils literal"><span class="pre">TypeError</span></tt></a>.</p>
<p>If there is no existing <em class="mailheader">MIME-Version</em> header one will be
added.  If there is no existing <em class="mailheader">Content-Type</em> header, one
will be added with a value of <em class="mimetype">text/plain</em>.  Whether the
<em class="mailheader">Content-Type</em> header already exists or not, its <tt class="docutils literal"><span class="pre">charset</span></tt>
parameter will be set to <em>charset.output_charset</em>.   If
<em>charset.input_charset</em> and <em>charset.output_charset</em> differ, the payload
will be re-encoded to the <em>output_charset</em>.  If there is no existing
<em class="mailheader">Content-Transfer-Encoding</em> header, then the payload will be
transfer-encoded, if needed, using the specified
<a class="reference internal" href="email.charset.html#email.charset.Charset" title="email.charset.Charset"><tt class="xref py py-class docutils literal"><span class="pre">Charset</span></tt></a>, and a header with the appropriate value
will be added.  If a <em class="mailheader">Content-Transfer-Encoding</em> header
already exists, the payload is assumed to already be correctly encoded
using that <em class="mailheader">Content-Transfer-Encoding</em> and is not modified.</p>
</dd></dl>

<dl class="method">
<dt id="email.message.Message.get_charset">
<tt class="descname">get_charset</tt><big>(</big><big>)</big><a class="headerlink" href="#email.message.Message.get_charset" title="Permalink to this definition">¶</a></dt>
<dd><p>Return the <a class="reference internal" href="email.charset.html#email.charset.Charset" title="email.charset.Charset"><tt class="xref py py-class docutils literal"><span class="pre">Charset</span></tt></a> instance associated with the
message&#8217;s payload.</p>
</dd></dl>

<p>The following methods implement a mapping-like interface for accessing the
message&#8217;s <span class="target" id="index-1"></span><a class="rfc reference external" href="http://tools.ietf.org/html/rfc2822.html"><strong>RFC 2822</strong></a> headers.  Note that there are some semantic differences
between these methods and a normal mapping (i.e. dictionary) interface.  For
example, in a dictionary there are no duplicate keys, but here there may be
duplicate message headers.  Also, in dictionaries there is no guaranteed
order to the keys returned by <a class="reference internal" href="#email.message.Message.keys" title="email.message.Message.keys"><tt class="xref py py-meth docutils literal"><span class="pre">keys()</span></tt></a>, but in a <a class="reference internal" href="#email.message.Message" title="email.message.Message"><tt class="xref py py-class docutils literal"><span class="pre">Message</span></tt></a> object,
headers are always returned in the order they appeared in the original
message, or were added to the message later.  Any header deleted and then
re-added are always appended to the end of the header list.</p>
<p>These semantic differences are intentional and are biased toward maximal
convenience.</p>
<p>Note that in all cases, any envelope header present in the message is not
included in the mapping interface.</p>
<p>In a model generated from bytes, any header values that (in contravention of
the RFCs) contain non-ASCII bytes will, when retrieved through this
interface, be represented as <a class="reference internal" href="email.header.html#email.header.Header" title="email.header.Header"><tt class="xref py py-class docutils literal"><span class="pre">Header</span></tt></a> objects with
a charset of <cite>unknown-8bit</cite>.</p>
<dl class="method">
<dt id="email.message.Message.__len__">
<tt class="descname">__len__</tt><big>(</big><big>)</big><a class="headerlink" href="#email.message.Message.__len__" title="Permalink to this definition">¶</a></dt>
<dd><p>Return the total number of headers, including duplicates.</p>
</dd></dl>

<dl class="method">
<dt id="email.message.Message.__contains__">
<tt class="descname">__contains__</tt><big>(</big><em>name</em><big>)</big><a class="headerlink" href="#email.message.Message.__contains__" title="Permalink to this definition">¶</a></dt>
<dd><p>Return true if the message object has a field named <em>name</em>. Matching is
done case-insensitively and <em>name</em> should not include the trailing colon.
Used for the <tt class="docutils literal"><span class="pre">in</span></tt> operator, e.g.:</p>
<div class="highlight-python3"><div class="highlight"><pre><span class="k">if</span> <span class="s">&#39;message-id&#39;</span> <span class="ow">in</span> <span class="n">myMessage</span><span class="p">:</span>
   <span class="nb">print</span><span class="p">(</span><span class="s">&#39;Message-ID:&#39;</span><span class="p">,</span> <span class="n">myMessage</span><span class="p">[</span><span class="s">&#39;message-id&#39;</span><span class="p">])</span>
</pre></div>
</div>
</dd></dl>

<dl class="method">
<dt id="email.message.Message.__getitem__">
<tt class="descname">__getitem__</tt><big>(</big><em>name</em><big>)</big><a class="headerlink" href="#email.message.Message.__getitem__" title="Permalink to this definition">¶</a></dt>
<dd><p>Return the value of the named header field.  <em>name</em> should not include the
colon field separator.  If the header is missing, <tt class="docutils literal"><span class="pre">None</span></tt> is returned; a
<a class="reference internal" href="exceptions.html#KeyError" title="KeyError"><tt class="xref py py-exc docutils literal"><span class="pre">KeyError</span></tt></a> is never raised.</p>
<p>Note that if the named field appears more than once in the message&#8217;s
headers, exactly which of those field values will be returned is
undefined.  Use the <a class="reference internal" href="#email.message.Message.get_all" title="email.message.Message.get_all"><tt class="xref py py-meth docutils literal"><span class="pre">get_all()</span></tt></a> method to get the values of all the
extant named headers.</p>
</dd></dl>

<dl class="method">
<dt id="email.message.Message.__setitem__">
<tt class="descname">__setitem__</tt><big>(</big><em>name</em>, <em>val</em><big>)</big><a class="headerlink" href="#email.message.Message.__setitem__" title="Permalink to this definition">¶</a></dt>
<dd><p>Add a header to the message with field name <em>name</em> and value <em>val</em>.  The
field is appended to the end of the message&#8217;s existing fields.</p>
<p>Note that this does <em>not</em> overwrite or delete any existing header with the same
name.  If you want to ensure that the new header is the only one present in the
message with field name <em>name</em>, delete the field first, e.g.:</p>
<div class="highlight-python3"><div class="highlight"><pre><span class="k">del</span> <span class="n">msg</span><span class="p">[</span><span class="s">&#39;subject&#39;</span><span class="p">]</span>
<span class="n">msg</span><span class="p">[</span><span class="s">&#39;subject&#39;</span><span class="p">]</span> <span class="o">=</span> <span class="s">&#39;Python roolz!&#39;</span>
</pre></div>
</div>
</dd></dl>

<dl class="method">
<dt id="email.message.Message.__delitem__">
<tt class="descname">__delitem__</tt><big>(</big><em>name</em><big>)</big><a class="headerlink" href="#email.message.Message.__delitem__" title="Permalink to this definition">¶</a></dt>
<dd><p>Delete all occurrences of the field with name <em>name</em> from the message&#8217;s
headers.  No exception is raised if the named field isn&#8217;t present in the
headers.</p>
</dd></dl>

<dl class="method">
<dt id="email.message.Message.keys">
<tt class="descname">keys</tt><big>(</big><big>)</big><a class="headerlink" href="#email.message.Message.keys" title="Permalink to this definition">¶</a></dt>
<dd><p>Return a list of all the message&#8217;s header field names.</p>
</dd></dl>

<dl class="method">
<dt id="email.message.Message.values">
<tt class="descname">values</tt><big>(</big><big>)</big><a class="headerlink" href="#email.message.Message.values" title="Permalink to this definition">¶</a></dt>
<dd><p>Return a list of all the message&#8217;s field values.</p>
</dd></dl>

<dl class="method">
<dt id="email.message.Message.items">
<tt class="descname">items</tt><big>(</big><big>)</big><a class="headerlink" href="#email.message.Message.items" title="Permalink to this definition">¶</a></dt>
<dd><p>Return a list of 2-tuples containing all the message&#8217;s field headers and
values.</p>
</dd></dl>

<dl class="method">
<dt id="email.message.Message.get">
<tt class="descname">get</tt><big>(</big><em>name</em>, <em>failobj=None</em><big>)</big><a class="headerlink" href="#email.message.Message.get" title="Permalink to this definition">¶</a></dt>
<dd><p>Return the value of the named header field.  This is identical to
<a class="reference internal" href="#email.message.Message.__getitem__" title="email.message.Message.__getitem__"><tt class="xref py py-meth docutils literal"><span class="pre">__getitem__()</span></tt></a> except that optional <em>failobj</em> is returned if the
named header is missing (defaults to <tt class="docutils literal"><span class="pre">None</span></tt>).</p>
</dd></dl>

<p>Here are some additional useful methods:</p>
<dl class="method">
<dt id="email.message.Message.get_all">
<tt class="descname">get_all</tt><big>(</big><em>name</em>, <em>failobj=None</em><big>)</big><a class="headerlink" href="#email.message.Message.get_all" title="Permalink to this definition">¶</a></dt>
<dd><p>Return a list of all the values for the field named <em>name</em>. If there are
no such named headers in the message, <em>failobj</em> is returned (defaults to
<tt class="docutils literal"><span class="pre">None</span></tt>).</p>
</dd></dl>

<dl class="method">
<dt id="email.message.Message.add_header">
<tt class="descname">add_header</tt><big>(</big><em>_name</em>, <em>_value</em>, <em>**_params</em><big>)</big><a class="headerlink" href="#email.message.Message.add_header" title="Permalink to this definition">¶</a></dt>
<dd><p>Extended header setting.  This method is similar to <a class="reference internal" href="#email.message.Message.__setitem__" title="email.message.Message.__setitem__"><tt class="xref py py-meth docutils literal"><span class="pre">__setitem__()</span></tt></a>
except that additional header parameters can be provided as keyword
arguments.  <em>_name</em> is the header field to add and <em>_value</em> is the
<em>primary</em> value for the header.</p>
<p>For each item in the keyword argument dictionary <em>_params</em>, the key is
taken as the parameter name, with underscores converted to dashes (since
dashes are illegal in Python identifiers).  Normally, the parameter will
be added as <tt class="docutils literal"><span class="pre">key=&quot;value&quot;</span></tt> unless the value is <tt class="docutils literal"><span class="pre">None</span></tt>, in which case
only the key will be added.  If the value contains non-ASCII characters,
it can be specified as a three tuple in the format
<tt class="docutils literal"><span class="pre">(CHARSET,</span> <span class="pre">LANGUAGE,</span> <span class="pre">VALUE)</span></tt>, where <tt class="docutils literal"><span class="pre">CHARSET</span></tt> is a string naming the
charset to be used to encode the value, <tt class="docutils literal"><span class="pre">LANGUAGE</span></tt> can usually be set
to <tt class="docutils literal"><span class="pre">None</span></tt> or the empty string (see <span class="target" id="index-2"></span><a class="rfc reference external" href="http://tools.ietf.org/html/rfc2231.html"><strong>RFC 2231</strong></a> for other possibilities),
and <tt class="docutils literal"><span class="pre">VALUE</span></tt> is the string value containing non-ASCII code points.  If
a three tuple is not passed and the value contains non-ASCII characters,
it is automatically encoded in <span class="target" id="index-3"></span><a class="rfc reference external" href="http://tools.ietf.org/html/rfc2231.html"><strong>RFC 2231</strong></a> format using a <tt class="docutils literal"><span class="pre">CHARSET</span></tt>
of <tt class="docutils literal"><span class="pre">utf-8</span></tt> and a <tt class="docutils literal"><span class="pre">LANGUAGE</span></tt> of <tt class="docutils literal"><span class="pre">None</span></tt>.</p>
<p>Here&#8217;s an example:</p>
<div class="highlight-python3"><div class="highlight"><pre><span class="n">msg</span><span class="o">.</span><span class="n">add_header</span><span class="p">(</span><span class="s">&#39;Content-Disposition&#39;</span><span class="p">,</span> <span class="s">&#39;attachment&#39;</span><span class="p">,</span> <span class="n">filename</span><span class="o">=</span><span class="s">&#39;bud.gif&#39;</span><span class="p">)</span>
</pre></div>
</div>
<p>This will add a header that looks like</p>
<div class="highlight-python3"><div class="highlight"><pre><span class="n">Content</span><span class="o">-</span><span class="n">Disposition</span><span class="p">:</span> <span class="n">attachment</span><span class="p">;</span> <span class="n">filename</span><span class="o">=</span><span class="s">&quot;bud.gif&quot;</span>
</pre></div>
</div>
<p>An example with non-ASCII characters:</p>
<div class="highlight-python3"><div class="highlight"><pre><span class="n">msg</span><span class="o">.</span><span class="n">add_header</span><span class="p">(</span><span class="s">&#39;Content-Disposition&#39;</span><span class="p">,</span> <span class="s">&#39;attachment&#39;</span><span class="p">,</span>
               <span class="n">filename</span><span class="o">=</span><span class="p">(</span><span class="s">&#39;iso-8859-1&#39;</span><span class="p">,</span> <span class="s">&#39;&#39;</span><span class="p">,</span> <span class="s">&#39;Fußballer.ppt&#39;</span><span class="p">))</span>
</pre></div>
</div>
<p>Which produces</p>
<div class="highlight-python3"><div class="highlight"><pre><span class="n">Content</span><span class="o">-</span><span class="n">Disposition</span><span class="p">:</span> <span class="n">attachment</span><span class="p">;</span> <span class="n">filename</span><span class="o">*=</span><span class="s">&quot;iso-8859-1&#39;&#39;Fu%DFballer.ppt&quot;</span>
</pre></div>
</div>
</dd></dl>

<dl class="method">
<dt id="email.message.Message.replace_header">
<tt class="descname">replace_header</tt><big>(</big><em>_name</em>, <em>_value</em><big>)</big><a class="headerlink" href="#email.message.Message.replace_header" title="Permalink to this definition">¶</a></dt>
<dd><p>Replace a header.  Replace the first header found in the message that
matches <em>_name</em>, retaining header order and field name case.  If no
matching header was found, a <a class="reference internal" href="exceptions.html#KeyError" title="KeyError"><tt class="xref py py-exc docutils literal"><span class="pre">KeyError</span></tt></a> is raised.</p>
</dd></dl>

<dl class="method">
<dt id="email.message.Message.get_content_type">
<tt class="descname">get_content_type</tt><big>(</big><big>)</big><a class="headerlink" href="#email.message.Message.get_content_type" title="Permalink to this definition">¶</a></dt>
<dd><p>Return the message&#8217;s content type.  The returned string is coerced to
lower case of the form <em class="mimetype">maintype/subtype</em>.  If there was no
<em class="mailheader">Content-Type</em> header in the message the default type as given
by <a class="reference internal" href="#email.message.Message.get_default_type" title="email.message.Message.get_default_type"><tt class="xref py py-meth docutils literal"><span class="pre">get_default_type()</span></tt></a> will be returned.  Since according to
<span class="target" id="index-4"></span><a class="rfc reference external" href="http://tools.ietf.org/html/rfc2045.html"><strong>RFC 2045</strong></a>, messages always have a default type, <a class="reference internal" href="#email.message.Message.get_content_type" title="email.message.Message.get_content_type"><tt class="xref py py-meth docutils literal"><span class="pre">get_content_type()</span></tt></a>
will always return a value.</p>
<p><span class="target" id="index-5"></span><a class="rfc reference external" href="http://tools.ietf.org/html/rfc2045.html"><strong>RFC 2045</strong></a> defines a message&#8217;s default type to be <em class="mimetype">text/plain</em>
unless it appears inside a <em class="mimetype">multipart/digest</em> container, in
which case it would be <em class="mimetype">message/rfc822</em>.  If the
<em class="mailheader">Content-Type</em> header has an invalid type specification,
<span class="target" id="index-6"></span><a class="rfc reference external" href="http://tools.ietf.org/html/rfc2045.html"><strong>RFC 2045</strong></a> mandates that the default type be <em class="mimetype">text/plain</em>.</p>
</dd></dl>

<dl class="method">
<dt id="email.message.Message.get_content_maintype">
<tt class="descname">get_content_maintype</tt><big>(</big><big>)</big><a class="headerlink" href="#email.message.Message.get_content_maintype" title="Permalink to this definition">¶</a></dt>
<dd><p>Return the message&#8217;s main content type.  This is the <em class="mimetype">maintype</em>
part of the string returned by <a class="reference internal" href="#email.message.Message.get_content_type" title="email.message.Message.get_content_type"><tt class="xref py py-meth docutils literal"><span class="pre">get_content_type()</span></tt></a>.</p>
</dd></dl>

<dl class="method">
<dt id="email.message.Message.get_content_subtype">
<tt class="descname">get_content_subtype</tt><big>(</big><big>)</big><a class="headerlink" href="#email.message.Message.get_content_subtype" title="Permalink to this definition">¶</a></dt>
<dd><p>Return the message&#8217;s sub-content type.  This is the <em class="mimetype">subtype</em>
part of the string returned by <a class="reference internal" href="#email.message.Message.get_content_type" title="email.message.Message.get_content_type"><tt class="xref py py-meth docutils literal"><span class="pre">get_content_type()</span></tt></a>.</p>
</dd></dl>

<dl class="method">
<dt id="email.message.Message.get_default_type">
<tt class="descname">get_default_type</tt><big>(</big><big>)</big><a class="headerlink" href="#email.message.Message.get_default_type" title="Permalink to this definition">¶</a></dt>
<dd><p>Return the default content type.  Most messages have a default content
type of <em class="mimetype">text/plain</em>, except for messages that are subparts of
<em class="mimetype">multipart/digest</em> containers.  Such subparts have a default
content type of <em class="mimetype">message/rfc822</em>.</p>
</dd></dl>

<dl class="method">
<dt id="email.message.Message.set_default_type">
<tt class="descname">set_default_type</tt><big>(</big><em>ctype</em><big>)</big><a class="headerlink" href="#email.message.Message.set_default_type" title="Permalink to this definition">¶</a></dt>
<dd><p>Set the default content type.  <em>ctype</em> should either be
<em class="mimetype">text/plain</em> or <em class="mimetype">message/rfc822</em>, although this is not
enforced.  The default content type is not stored in the
<em class="mailheader">Content-Type</em> header.</p>
</dd></dl>

<dl class="method">
<dt id="email.message.Message.get_params">
<tt class="descname">get_params</tt><big>(</big><em>failobj=None</em>, <em>header='content-type'</em>, <em>unquote=True</em><big>)</big><a class="headerlink" href="#email.message.Message.get_params" title="Permalink to this definition">¶</a></dt>
<dd><p>Return the message&#8217;s <em class="mailheader">Content-Type</em> parameters, as a list.
The elements of the returned list are 2-tuples of key/value pairs, as
split on the <tt class="docutils literal"><span class="pre">'='</span></tt> sign.  The left hand side of the <tt class="docutils literal"><span class="pre">'='</span></tt> is the key,
while the right hand side is the value.  If there is no <tt class="docutils literal"><span class="pre">'='</span></tt> sign in
the parameter the value is the empty string, otherwise the value is as
described in <a class="reference internal" href="#email.message.Message.get_param" title="email.message.Message.get_param"><tt class="xref py py-meth docutils literal"><span class="pre">get_param()</span></tt></a> and is unquoted if optional <em>unquote</em> is
<tt class="docutils literal"><span class="pre">True</span></tt> (the default).</p>
<p>Optional <em>failobj</em> is the object to return if there is no
<em class="mailheader">Content-Type</em> header.  Optional <em>header</em> is the header to
search instead of <em class="mailheader">Content-Type</em>.</p>
</dd></dl>

<dl class="method">
<dt id="email.message.Message.get_param">
<tt class="descname">get_param</tt><big>(</big><em>param</em>, <em>failobj=None</em>, <em>header='content-type'</em>, <em>unquote=True</em><big>)</big><a class="headerlink" href="#email.message.Message.get_param" title="Permalink to this definition">¶</a></dt>
<dd><p>Return the value of the <em class="mailheader">Content-Type</em> header&#8217;s parameter
<em>param</em> as a string.  If the message has no <em class="mailheader">Content-Type</em>
header or if there is no such parameter, then <em>failobj</em> is returned
(defaults to <tt class="docutils literal"><span class="pre">None</span></tt>).</p>
<p>Optional <em>header</em> if given, specifies the message header to use instead of
<em class="mailheader">Content-Type</em>.</p>
<p>Parameter keys are always compared case insensitively.  The return value
can either be a string, or a 3-tuple if the parameter was <span class="target" id="index-7"></span><a class="rfc reference external" href="http://tools.ietf.org/html/rfc2231.html"><strong>RFC 2231</strong></a>
encoded.  When it&#8217;s a 3-tuple, the elements of the value are of the form
<tt class="docutils literal"><span class="pre">(CHARSET,</span> <span class="pre">LANGUAGE,</span> <span class="pre">VALUE)</span></tt>.  Note that both <tt class="docutils literal"><span class="pre">CHARSET</span></tt> and
<tt class="docutils literal"><span class="pre">LANGUAGE</span></tt> can be <tt class="docutils literal"><span class="pre">None</span></tt>, in which case you should consider <tt class="docutils literal"><span class="pre">VALUE</span></tt>
to be encoded in the <tt class="docutils literal"><span class="pre">us-ascii</span></tt> charset.  You can usually ignore
<tt class="docutils literal"><span class="pre">LANGUAGE</span></tt>.</p>
<p>If your application doesn&#8217;t care whether the parameter was encoded as in
<span class="target" id="index-8"></span><a class="rfc reference external" href="http://tools.ietf.org/html/rfc2231.html"><strong>RFC 2231</strong></a>, you can collapse the parameter value by calling
<a class="reference internal" href="email.util.html#email.utils.collapse_rfc2231_value" title="email.utils.collapse_rfc2231_value"><tt class="xref py py-func docutils literal"><span class="pre">email.utils.collapse_rfc2231_value()</span></tt></a>, passing in the return value
from <a class="reference internal" href="#email.message.Message.get_param" title="email.message.Message.get_param"><tt class="xref py py-meth docutils literal"><span class="pre">get_param()</span></tt></a>.  This will return a suitably decoded Unicode
string when the value is a tuple, or the original string unquoted if it
isn&#8217;t.  For example:</p>
<div class="highlight-python3"><div class="highlight"><pre><span class="n">rawparam</span> <span class="o">=</span> <span class="n">msg</span><span class="o">.</span><span class="n">get_param</span><span class="p">(</span><span class="s">&#39;foo&#39;</span><span class="p">)</span>
<span class="n">param</span> <span class="o">=</span> <span class="n">email</span><span class="o">.</span><span class="n">utils</span><span class="o">.</span><span class="n">collapse_rfc2231_value</span><span class="p">(</span><span class="n">rawparam</span><span class="p">)</span>
</pre></div>
</div>
<p>In any case, the parameter value (either the returned string, or the
<tt class="docutils literal"><span class="pre">VALUE</span></tt> item in the 3-tuple) is always unquoted, unless <em>unquote</em> is set
to <tt class="docutils literal"><span class="pre">False</span></tt>.</p>
</dd></dl>

<dl class="method">
<dt id="email.message.Message.set_param">
<tt class="descname">set_param</tt><big>(</big><em>param</em>, <em>value</em>, <em>header='Content-Type'</em>, <em>requote=True</em>, <em>charset=None</em>, <em>language=''</em>, <em>replace=False</em><big>)</big><a class="headerlink" href="#email.message.Message.set_param" title="Permalink to this definition">¶</a></dt>
<dd><p>Set a parameter in the <em class="mailheader">Content-Type</em> header.  If the
parameter already exists in the header, its value will be replaced with
<em>value</em>.  If the <em class="mailheader">Content-Type</em> header as not yet been defined
for this message, it will be set to <em class="mimetype">text/plain</em> and the new
parameter value will be appended as per <span class="target" id="index-9"></span><a class="rfc reference external" href="http://tools.ietf.org/html/rfc2045.html"><strong>RFC 2045</strong></a>.</p>
<p>Optional <em>header</em> specifies an alternative header to
<em class="mailheader">Content-Type</em>, and all parameters will be quoted as necessary
unless optional <em>requote</em> is <tt class="docutils literal"><span class="pre">False</span></tt> (the default is <tt class="docutils literal"><span class="pre">True</span></tt>).</p>
<p>If optional <em>charset</em> is specified, the parameter will be encoded
according to <span class="target" id="index-10"></span><a class="rfc reference external" href="http://tools.ietf.org/html/rfc2231.html"><strong>RFC 2231</strong></a>. Optional <em>language</em> specifies the RFC 2231
language, defaulting to the empty string.  Both <em>charset</em> and <em>language</em>
should be strings.</p>
<p>If <em>replace</em> is <tt class="docutils literal"><span class="pre">False</span></tt> (the default) the header is moved to the
end of the list of headers.  If <em>replace</em> is <tt class="docutils literal"><span class="pre">True</span></tt>, the header
will be updated in place.</p>
<div class="versionchanged">
<p><span class="versionmodified">Changed in version 3.4: </span><tt class="docutils literal"><span class="pre">replace</span></tt> keyword was added.</p>
</div>
</dd></dl>

<dl class="method">
<dt id="email.message.Message.del_param">
<tt class="descname">del_param</tt><big>(</big><em>param</em>, <em>header='content-type'</em>, <em>requote=True</em><big>)</big><a class="headerlink" href="#email.message.Message.del_param" title="Permalink to this definition">¶</a></dt>
<dd><p>Remove the given parameter completely from the <em class="mailheader">Content-Type</em>
header.  The header will be re-written in place without the parameter or
its value.  All values will be quoted as necessary unless <em>requote</em> is
<tt class="docutils literal"><span class="pre">False</span></tt> (the default is <tt class="docutils literal"><span class="pre">True</span></tt>).  Optional <em>header</em> specifies an
alternative to <em class="mailheader">Content-Type</em>.</p>
</dd></dl>

<dl class="method">
<dt id="email.message.Message.set_type">
<tt class="descname">set_type</tt><big>(</big><em>type</em>, <em>header='Content-Type'</em>, <em>requote=True</em><big>)</big><a class="headerlink" href="#email.message.Message.set_type" title="Permalink to this definition">¶</a></dt>
<dd><p>Set the main type and subtype for the <em class="mailheader">Content-Type</em>
header. <em>type</em> must be a string in the form <em class="mimetype">maintype/subtype</em>,
otherwise a <a class="reference internal" href="exceptions.html#ValueError" title="ValueError"><tt class="xref py py-exc docutils literal"><span class="pre">ValueError</span></tt></a> is raised.</p>
<p>This method replaces the <em class="mailheader">Content-Type</em> header, keeping all
the parameters in place.  If <em>requote</em> is <tt class="docutils literal"><span class="pre">False</span></tt>, this leaves the
existing header&#8217;s quoting as is, otherwise the parameters will be quoted
(the default).</p>
<p>An alternative header can be specified in the <em>header</em> argument. When the
<em class="mailheader">Content-Type</em> header is set a <em class="mailheader">MIME-Version</em>
header is also added.</p>
</dd></dl>

<dl class="method">
<dt id="email.message.Message.get_filename">
<tt class="descname">get_filename</tt><big>(</big><em>failobj=None</em><big>)</big><a class="headerlink" href="#email.message.Message.get_filename" title="Permalink to this definition">¶</a></dt>
<dd><p>Return the value of the <tt class="docutils literal"><span class="pre">filename</span></tt> parameter of the
<em class="mailheader">Content-Disposition</em> header of the message.  If the header
does not have a <tt class="docutils literal"><span class="pre">filename</span></tt> parameter, this method falls back to looking
for the <tt class="docutils literal"><span class="pre">name</span></tt> parameter on the <em class="mailheader">Content-Type</em> header.  If
neither is found, or the header is missing, then <em>failobj</em> is returned.
The returned string will always be unquoted as per
<a class="reference internal" href="email.util.html#email.utils.unquote" title="email.utils.unquote"><tt class="xref py py-func docutils literal"><span class="pre">email.utils.unquote()</span></tt></a>.</p>
</dd></dl>

<dl class="method">
<dt id="email.message.Message.get_boundary">
<tt class="descname">get_boundary</tt><big>(</big><em>failobj=None</em><big>)</big><a class="headerlink" href="#email.message.Message.get_boundary" title="Permalink to this definition">¶</a></dt>
<dd><p>Return the value of the <tt class="docutils literal"><span class="pre">boundary</span></tt> parameter of the
<em class="mailheader">Content-Type</em> header of the message, or <em>failobj</em> if either
the header is missing, or has no <tt class="docutils literal"><span class="pre">boundary</span></tt> parameter.  The returned
string will always be unquoted as per <a class="reference internal" href="email.util.html#email.utils.unquote" title="email.utils.unquote"><tt class="xref py py-func docutils literal"><span class="pre">email.utils.unquote()</span></tt></a>.</p>
</dd></dl>

<dl class="method">
<dt id="email.message.Message.set_boundary">
<tt class="descname">set_boundary</tt><big>(</big><em>boundary</em><big>)</big><a class="headerlink" href="#email.message.Message.set_boundary" title="Permalink to this definition">¶</a></dt>
<dd><p>Set the <tt class="docutils literal"><span class="pre">boundary</span></tt> parameter of the <em class="mailheader">Content-Type</em> header to
<em>boundary</em>.  <a class="reference internal" href="#email.message.Message.set_boundary" title="email.message.Message.set_boundary"><tt class="xref py py-meth docutils literal"><span class="pre">set_boundary()</span></tt></a> will always quote <em>boundary</em> if
necessary.  A <a class="reference internal" href="email.errors.html#email.errors.HeaderParseError" title="email.errors.HeaderParseError"><tt class="xref py py-exc docutils literal"><span class="pre">HeaderParseError</span></tt></a> is raised if the
message object has no <em class="mailheader">Content-Type</em> header.</p>
<p>Note that using this method is subtly different than deleting the old
<em class="mailheader">Content-Type</em> header and adding a new one with the new
boundary via <a class="reference internal" href="#email.message.Message.add_header" title="email.message.Message.add_header"><tt class="xref py py-meth docutils literal"><span class="pre">add_header()</span></tt></a>, because <a class="reference internal" href="#email.message.Message.set_boundary" title="email.message.Message.set_boundary"><tt class="xref py py-meth docutils literal"><span class="pre">set_boundary()</span></tt></a> preserves
the order of the <em class="mailheader">Content-Type</em> header in the list of
headers. However, it does <em>not</em> preserve any continuation lines which may
have been present in the original <em class="mailheader">Content-Type</em> header.</p>
</dd></dl>

<dl class="method">
<dt id="email.message.Message.get_content_charset">
<tt class="descname">get_content_charset</tt><big>(</big><em>failobj=None</em><big>)</big><a class="headerlink" href="#email.message.Message.get_content_charset" title="Permalink to this definition">¶</a></dt>
<dd><p>Return the <tt class="docutils literal"><span class="pre">charset</span></tt> parameter of the <em class="mailheader">Content-Type</em> header,
coerced to lower case.  If there is no <em class="mailheader">Content-Type</em> header, or if
that header has no <tt class="docutils literal"><span class="pre">charset</span></tt> parameter, <em>failobj</em> is returned.</p>
<p>Note that this method differs from <a class="reference internal" href="#email.message.Message.get_charset" title="email.message.Message.get_charset"><tt class="xref py py-meth docutils literal"><span class="pre">get_charset()</span></tt></a> which returns the
<a class="reference internal" href="email.charset.html#email.charset.Charset" title="email.charset.Charset"><tt class="xref py py-class docutils literal"><span class="pre">Charset</span></tt></a> instance for the default encoding of the message body.</p>
</dd></dl>

<dl class="method">
<dt id="email.message.Message.get_charsets">
<tt class="descname">get_charsets</tt><big>(</big><em>failobj=None</em><big>)</big><a class="headerlink" href="#email.message.Message.get_charsets" title="Permalink to this definition">¶</a></dt>
<dd><p>Return a list containing the character set names in the message.  If the
message is a <em class="mimetype">multipart</em>, then the list will contain one element
for each subpart in the payload, otherwise, it will be a list of length 1.</p>
<p>Each item in the list will be a string which is the value of the
<tt class="docutils literal"><span class="pre">charset</span></tt> parameter in the <em class="mailheader">Content-Type</em> header for the
represented subpart.  However, if the subpart has no
<em class="mailheader">Content-Type</em> header, no <tt class="docutils literal"><span class="pre">charset</span></tt> parameter, or is not of
the <em class="mimetype">text</em> main MIME type, then that item in the returned list
will be <em>failobj</em>.</p>
</dd></dl>

<dl class="method">
<dt id="email.message.Message.walk">
<tt class="descname">walk</tt><big>(</big><big>)</big><a class="headerlink" href="#email.message.Message.walk" title="Permalink to this definition">¶</a></dt>
<dd><p>The <a class="reference internal" href="#email.message.Message.walk" title="email.message.Message.walk"><tt class="xref py py-meth docutils literal"><span class="pre">walk()</span></tt></a> method is an all-purpose generator which can be used to
iterate over all the parts and subparts of a message object tree, in
depth-first traversal order.  You will typically use <a class="reference internal" href="#email.message.Message.walk" title="email.message.Message.walk"><tt class="xref py py-meth docutils literal"><span class="pre">walk()</span></tt></a> as the
iterator in a <tt class="docutils literal"><span class="pre">for</span></tt> loop; each iteration returns the next subpart.</p>
<p>Here&#8217;s an example that prints the MIME type of every part of a multipart
message structure:</p>
<div class="highlight-python3"><div class="highlight"><pre><span class="gp">&gt;&gt;&gt; </span><span class="k">for</span> <span class="n">part</span> <span class="ow">in</span> <span class="n">msg</span><span class="o">.</span><span class="n">walk</span><span class="p">():</span>
<span class="gp">... </span>    <span class="nb">print</span><span class="p">(</span><span class="n">part</span><span class="o">.</span><span class="n">get_content_type</span><span class="p">())</span>
<span class="go">multipart/report</span>
<span class="go">text/plain</span>
<span class="go">message/delivery-status</span>
<span class="go">text/plain</span>
<span class="go">text/plain</span>
<span class="go">message/rfc822</span>
<span class="go">text/plain</span>
</pre></div>
</div>
<p><tt class="docutils literal"><span class="pre">walk</span></tt> iterates over the subparts of any part where
<a class="reference internal" href="#email.message.Message.is_multipart" title="email.message.Message.is_multipart"><tt class="xref py py-meth docutils literal"><span class="pre">is_multipart()</span></tt></a> returns <tt class="docutils literal"><span class="pre">True</span></tt>, even though
<tt class="docutils literal"><span class="pre">msg.get_content_maintype()</span> <span class="pre">==</span> <span class="pre">'multipart'</span></tt> may return <tt class="docutils literal"><span class="pre">False</span></tt>.  We
can see this in our example by making use of the <tt class="docutils literal"><span class="pre">_structure</span></tt> debug
helper function:</p>
<div class="highlight-python3"><div class="highlight"><pre><span class="gp">&gt;&gt;&gt; </span><span class="k">for</span> <span class="n">part</span> <span class="ow">in</span> <span class="n">msg</span><span class="o">.</span><span class="n">walk</span><span class="p">():</span>
<span class="gp">... </span>    <span class="nb">print</span><span class="p">(</span><span class="n">part</span><span class="o">.</span><span class="n">get_content_maintype</span><span class="p">()</span> <span class="o">==</span> <span class="s">&#39;multipart&#39;</span><span class="p">),</span>
<span class="gp">... </span>          <span class="n">part</span><span class="o">.</span><span class="n">is_multipart</span><span class="p">())</span>
<span class="go">True True</span>
<span class="go">False False</span>
<span class="go">False True</span>
<span class="go">False False</span>
<span class="go">False False</span>
<span class="go">False True</span>
<span class="go">False False</span>
<span class="gp">&gt;&gt;&gt; </span><span class="n">_structure</span><span class="p">(</span><span class="n">msg</span><span class="p">)</span>
<span class="go">multipart/report</span>
<span class="go">    text/plain</span>
<span class="go">message/delivery-status</span>
<span class="go">    text/plain</span>
<span class="go">    text/plain</span>
<span class="go">message/rfc822</span>
<span class="go">    text/plain</span>
</pre></div>
</div>
<p>Here the <tt class="docutils literal"><span class="pre">message</span></tt> parts are not <tt class="docutils literal"><span class="pre">multiparts</span></tt>, but they do contain
subparts. <tt class="docutils literal"><span class="pre">is_multipart()</span></tt> returns <tt class="docutils literal"><span class="pre">True</span></tt> and <tt class="docutils literal"><span class="pre">walk</span></tt> descends
into the subparts.</p>
</dd></dl>

<p><a class="reference internal" href="#email.message.Message" title="email.message.Message"><tt class="xref py py-class docutils literal"><span class="pre">Message</span></tt></a> objects can also optionally contain two instance attributes,
which can be used when generating the plain text of a MIME message.</p>
<dl class="attribute">
<dt id="email.message.Message.preamble">
<tt class="descname">preamble</tt><a class="headerlink" href="#email.message.Message.preamble" title="Permalink to this definition">¶</a></dt>
<dd><p>The format of a MIME document allows for some text between the blank line
following the headers, and the first multipart boundary string. Normally,
this text is never visible in a MIME-aware mail reader because it falls
outside the standard MIME armor.  However, when viewing the raw text of
the message, or when viewing the message in a non-MIME aware reader, this
text can become visible.</p>
<p>The <em>preamble</em> attribute contains this leading extra-armor text for MIME
documents.  When the <a class="reference internal" href="email.parser.html#email.parser.Parser" title="email.parser.Parser"><tt class="xref py py-class docutils literal"><span class="pre">Parser</span></tt></a> discovers some text
after the headers but before the first boundary string, it assigns this
text to the message&#8217;s <em>preamble</em> attribute.  When the
<a class="reference internal" href="email.generator.html#email.generator.Generator" title="email.generator.Generator"><tt class="xref py py-class docutils literal"><span class="pre">Generator</span></tt></a> is writing out the plain text
representation of a MIME message, and it finds the
message has a <em>preamble</em> attribute, it will write this text in the area
between the headers and the first boundary.  See <a class="reference internal" href="email.parser.html#module-email.parser" title="email.parser: Parse flat text email messages to produce a message object structure."><tt class="xref py py-mod docutils literal"><span class="pre">email.parser</span></tt></a> and
<a class="reference internal" href="email.generator.html#module-email.generator" title="email.generator: Generate flat text email messages from a message structure."><tt class="xref py py-mod docutils literal"><span class="pre">email.generator</span></tt></a> for details.</p>
<p>Note that if the message object has no preamble, the <em>preamble</em> attribute
will be <tt class="docutils literal"><span class="pre">None</span></tt>.</p>
</dd></dl>

<dl class="attribute">
<dt id="email.message.Message.epilogue">
<tt class="descname">epilogue</tt><a class="headerlink" href="#email.message.Message.epilogue" title="Permalink to this definition">¶</a></dt>
<dd><p>The <em>epilogue</em> attribute acts the same way as the <em>preamble</em> attribute,
except that it contains text that appears between the last boundary and
the end of the message.</p>
<p>You do not need to set the epilogue to the empty string in order for the
<a class="reference internal" href="email.generator.html#email.generator.Generator" title="email.generator.Generator"><tt class="xref py py-class docutils literal"><span class="pre">Generator</span></tt></a> to print a newline at the end of the
file.</p>
</dd></dl>

<dl class="attribute">
<dt id="email.message.Message.defects">
<tt class="descname">defects</tt><a class="headerlink" href="#email.message.Message.defects" title="Permalink to this definition">¶</a></dt>
<dd><p>The <em>defects</em> attribute contains a list of all the problems found when
parsing this message.  See <a class="reference internal" href="email.errors.html#module-email.errors" title="email.errors: The exception classes used by the email package."><tt class="xref py py-mod docutils literal"><span class="pre">email.errors</span></tt></a> for a detailed description
of the possible parsing defects.</p>
</dd></dl>

</dd></dl>

</div>


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